Mobula rays are closely related to their larger cousins, the manta ray. Some species of mobula can measure as much as 17 feet long and weigh over a ton.

Octavio told Business Insider that the massive swarm of devil rays he saw in 2011 arrived in a region near the Gulf of California in January and stayed through May.

Tens to hundreds of rays will leap out of the water at a time. Researchers have noticed that usually the jumpers are located along the outskirts of the swarm, which could be the key to understanding why they jump.

Notice that the rays don't dive head-first as they land. Instead, they do a massive belly flop.

This belly flop generates a loud boom that some suspect could scare potential prey, like shrimp, closer toward the swarm, making an easy meal for the rays under the surface.

Sometimes they get a little out of control, like this ray that does a somersault in mid-air, landing on its back instead of its belly:

Many mobula species like to travel in large packs, which makes them especially vulnerable to fishing. And, in fact, many species of mobula rays are endangered.

In February 2013, fisherman from Gaza City in Palestine caught over 200 devil rays in just two days. Some of them are shown here in a picture taken by Ahmed Zakot:

The region where Octavio took these amazing photos has been protected from fishing for about two decades. He and other researchers have been visiting this region for years to study how the ecosystem has recovered.

Although scientists don't know why these gigantic fish jump, they have at least measured how high: some of the most spectacular jumps can reach over 6.5 feet above the surface.

And it's not just their jumping abilities that are extraordinary: In a recent study, a team of researchers discovered that a certain species of these devil rays, Mobula tarapacana, is among the deepest-diving ocean animals in the world, reaching depths over 6500 feet below the surface -- well over a mile deep!

Despite returning to the same spot each year, Octavio has not seen a swarm of mobula rays anything like the one he encountered in 2011. He thinks that the temperatures have been too warm for the rays' return.

Octavio hopes to one day see these majestic fish near the California coast again. And next time, he says that he plans to record the sounds these devil rays make when they hit the water in hopes of discovering the secret behind their mysterious jumping behaviour.

Now that you know fish can fly, check out some of the other surprising abilities of different animals in the animal kingdom: